Method of and apparatus for the piecing up of yarns

ABSTRACT

The piecing-up of an open-end spinning machine is achieved by forming a first reserve length of yarn between open-end spinning means and delivery rollers of the machine and by forming a second reserve length of yarn between the delivery rollers and a take-up means of the machine. With the delivery of yarn halted, control means release the first and second reserve lengths of yarn to enable them to enter the open-end spinning means and to be taken up by the take-up means respectively. The control means also control the operation of the delivery rollers to commence or recommence the formation delivery and take-up of yarn.

O Umted States Patent 1 [111 3,911,658

Smith Oct. 14, 1975 [54] METHOD OF AND APPARATUS FOR TI-{E 3,803,823 4/1974 Niestros et al. 57/34 R PIECING UP 0F YARNS 3,815,347 6/1974 Nemec et al 57/34 R 3,821,878 7/1974 Parsons 57/34 R [75] Inventor: Alan Smith, Accrington, England [73] Assignee: Platt International Limited, England Primary Examiner-John Petrakes Attorney, Agent, or Firm-Watson, Cole, Grindle & [22] Filed: Dec. 12, 1973 Watson [21] Appl. No.: 423,897

[57] ABSTRACT [30] Foreign Application Priority Data The piecing-up of an open-end spinning machine is Dec 14 1972 United Kin dom 57837/72 achleved by forming a first reserve length of yarn bei g tween open-end spinning means and delivery rollers of the machine and by forming a second reserve length 57/34 %?fi Z of yarn between the delivery rollers and a take-up [58] i 58 89 58 95 means of the machine. With the delivery of yarn 57/80 halted, control means release the first and second reserve lengths of yarn to enable them to enter the [56] References Cited open-end spinning means and to be taken up by the take-up means respectively. The control means also UNITED STATES PATENTS control the operation of the delivery rollers to com- 3.354,631 11/1967 Elias 6t mence or re-commence the formation delivery and 3,455,095 7/1969 Makeham et a1. 57 34 R take u f am 3,680,300 8/1972 Landwehrkamp 57/34 R p y 3,685,267 8/1972 Landwehrkamp et a1. 57 34 R 25 Claims, 3 Drawing Figures U.S. Patant Oct. 14, 1975 Sheet 1 of3 3,911,658 r US. Patent Oct. 14, 1975 Sheet 2 of 3 3,911,658

US. Patent Oct. 14, 1975 Sheet 3 of3 3,911,658

METHOD OF AND APPARATUS FOR THE PIECING UP OF YARNS The invention relates to a method of and an apparatus for piecing-up a yarn for open-end spinning machines of the kind in which, in use, yarn is formed in an open-end spinning means and travels in a first path to yarn delivery means and in a second path from the yarn delivery means to yarn take-up means hereinafter referred to as an open-end spinning machine of the kind referred to.

In open-end spinning machines it is necessary to piece up a yarn at the start of a spinning operation or following an end breakage or following an interruption of the spinning process. One previously proposed arrangement for piecing-up an open-end spinning machine of the kind referred to involves the reversal of the direction of delivery of the yarn delivery means and of yarn take-up means so that an end of yarn of the yarn take-up means is returned into the spinning means to contact and twist in fibres fed to the spinning means. After the yarn delivery means and take-up means have been reversed for a predetermined time, they are operated in a forward direction to withdraw spun yarn from the spinning means and to take-up the yarn on the yarn take-up means.

In another previously proposed arrangement a single reserve length of yarn has been provided either in the first yarn path between the spinning rotor and the delivery rollers or in the second yarn path between the delivery rollers and the yarn take-up means. When it is desired to effect a yarn piecing-up operation the single reserve length of yarn is released so that the end of yarn returns into the spinning means to commence or recommence the formation of yarn.

Neither of the aforementioned proposals have proved to be sufficiently efficient in open-end spinning machines operating at high rates of production.

It is an object of the invention to provide improved yarn piecing-up for an open-end spinning machine.

According to a first aspect of the present invention there is provided a method of piecing-up a yarn for an open-end spinning machine of the kind referred to comprising forming the yarn into an extended first yarn path and into an extended second yarn path to provide first and second reserve lengths of yarn respectively, and then, releasing the first and second reserve lengths of yarn, with the delivery of yarn halted to enable the first reserve length of yarn to enter the open-end spinning means and to enable the second reserve length of yarn to be taken-up by the take-up means and making operative the yarn delivery means to commence or recommence the formation, delivery and take-up of yarn.

According to a second aspect of the present invention there is provided apparatus for piecing-up yarn for an open-end spinning machine of the kind referred to, comprising a first yarn reserve length holding means for holding the yarn in an extended first yarn path and a second yarn reserve length holding means for holding the yarn in an extended second yarn path, and control means which, in use, with the delivery of the yarn halted, release the yarn from the first and second yarn reserve length holding means to enable the first reserve length of yarn to enter the open-end spinning means and to enable the second reserve length of yarn to be taken up by the take-up means and which make operative the yarn delivery means to commence or recommence the formation, delivery and take-up of yarn.

The control means preferably release the yarn from the first and second yarn reserve length holding means before making operative the yarn delivery means and preferably the control means include adjustable timing means which determine the time interval between the release of the yarn and the operation of the yarn delivery means.

According to a third aspect of the invention, there is provided an open-end spinning machine of the kind referred to and including apparatus for piecing-up a yarn of any of the kinds referred to above.

The following is a more detailed description of one embodiment of the invention, by way of example, reference being made to the accompanying drawings in which:

FIG. 1 is a partial side elevation of an open-end spinning machine including a yarn piecing-up apparatus according to the invention.

FIG. 2 is a side elevation partially in section of the yarn piecing-up apparatus, and,

FIG. 3 is a cross-section on the line III-III of the yarn piecing-up apparatus of FIG. 2.

Referring to FIG. 1, a sliver S is delivered to an opening roller 1 by a nip formed between a feed roller 2 and a spring loaded feed pedal 3. The sliver S is opened by the opening roller 1 which delivers fibres in discrete form in an airstream along a fibre feed tube 4 to a fibre collecting surface of a spinning rotor 5 which is caused to rotate at a high speed by drive means (not shown). The fibres collected on the fibre collecting surface are twisted into the tail end of a spun yarn Y which is withdrawn from the rotor through a yarn delivery tube 6 by a pair of delivery rollers 7, 8. After passing through the nip between the delivery rollers 7, 8 the yarn Y passes around guide bars 9, 10 then to yarn take-up means where it passes around a rotating grooved traverse drum 11 to be wound onto a package 12. The package 12 is in frictional driving contact with the grooved traverse drum 11.

For yarn piecing-up a yarn piecing-up apparatus 13 is provided. This apparatus may be portable so that it may be transferred from one open-end spinning station to another as required, or such a device may be provided at each spinning station. In the former case, as shown in the drawings, the device is positioned adjacent the delivery rollers 7, 8 and detachably-mounted on a pin 56 carried by means of a support bracket 15 connected to the machine frame 14. The bracket 15 carries a housing 16 for the apparatus.

Referring now to FIGS. 2 and 3, an operating member 17 is slidably mounted within the housing 16 and has two latch members l8, l9 rigidly connected thereto which protrude through slots 20, 21 respectively formed in the housing 16. Members 22, 23 are attached to the housing 16 and co-operate, respectively, with latch members l8, 19 in the position shown in FIG. 2 to form first and second yarn holding means respectively. Member 23 is adjustable to provide for different sizes of reserve lengths. The operating member 17 also includes a cam surface 24, which, in operation, serves to actuate a micro-switch 25 mounted in the housing 16.

A slide actuating lever 26 is pivotally mounted at one end on a pivot pin 27 and has at the opposite end two finger members 28 and 29 positioned on each side of a cranked portion of the operating member 17 (as best seen in FIG. 3). A leaf spring 37 presses at one end against pin 36 attached to slide actuating lever 26 and is anchored at its opposite end to pivot pin 27. A trigger 32 is pivotally mounted on the housing 16 and has two arms 33 and 34. One arm 34 is provided with a stop surface 35 against which a pin 36 attached to the slide actuating lever 26 engages, thus preventing actuation of the slide actuation lever 26 against the influence of spring 37.

A yarn re-engaging mechanism for inserting the yarn Y into the nip of the delivery rollers 7, 8 is also mounted with the housing 16. This mechanism comprises a shaft 38 rotatably supported at each end in bearings 39, 40 attached to the housing 16. A spring 41 is attached at one end to the housing 16 and at the other end to a pin 42 protruding from the shaft 38 and tends to rotate the shaft 38 in a clockwise direction, as seen in FIG. 3. A finger member 55 extends from the shaft 38 and bears against the housing 16 to prevent rotation of the shaft 38 by the spring 41. Also provided on the shaft 38 are two fork members 43, 44 which extend from the shaft 38 outside the housing 16 and terminate in the vicinity of the delivery roller nip. One fork member 43 lies adjacent the delivery roller nip on the yarn take-up side thereof and the other fork member 44 lies adjacent to the delivery rollers nip on the spinning rotor side thereof. A projection 45 on the shaft 38 is provided with a pin 46 which in operation, is contacted by an actuating member 47 attached to the operating member 17.

As seen in FIG. 1, a package lifting and lowering mechanism comprises a bracket 60 fastened to a machine frame-member 48. Supported on the bracket 60 is a pneumatic cylinder 49 having a piston rod 50 extending through the frame member 48 and connected pivotally to a package displacing arm 51. The package displacing arm is pivotally mounted on support 52 and is under the influence of a spring 53 the force of which tends to oppose movement of the piston rod 50 in a direction towards the package 12.

The machine described above with reference to the drawing operates as follows: If it is desired to commence spinning either following an end breakage or upon starting up the machine, the yarn piecing apparatus 13 is attached to the machine in the vicinity of the delivery rollers 7, 8 assuming that a portable yarn piecing device is employed. The yarn package 12 or the tube on which the yarn Y is to be wound is disengaged from the grooved traverse drum 11. The yarn breakage detector 61 serves to initiate the stopping of feed roller 2 to prevent further delivery of fibres into the spinning rotor 5.

A yarn end is taken from the package 12 and then around the guide bar and around the first yarn holding means 18, 22. The yarn is then pressed against the housing 16 by means of the finger member 55 and then passed over a guide 54 attached to the housing 16. The yarn is then engaged with the fork members 43, 44. The yarn is next passed around the second yarn holding means 19, 23, and thence into the yarn delivery tube 6. A suction airstream, set up in the yarn delivery tube 6 either by the rotation spinning rotor 5 or by an external source, retains the yarn in the delivery tube 6. Assuming that opening roller 1 is also in rotation, the piecingup operation continues as follows.

The operative draws back the trigger 32 and thus releases the pin 36 attached to the slide actuating lever 26 from engagement with the stop surface 35. The operating member 17 is thus released from a first position and caused to move towards the delivery rollers 7, 8 by means of the spring 37 acting through the slide actuating lever 26. In consequence, latch members 18 and 19 move away from members 22 and 23 and in a second position of the operating member 17 release the yarn Y. The operating member 17 continues its movement to a third position in which the cam surface 24 actuates the micro-switch 25 which initiates rotation of feed roller 2 so that fibres commence to be fed into the spinning rotor 5. The micro-switch 25 also initiates the removal of air from pneumatic cylinder 49 such that piston rod is withdrawn into the cylinder and therefore package 12 comes into driving contact with the grooved traverse drum 11. Thus the reserve length of yarn between the spinning rotor and the yarn delivery means 7, 8 enables the end of yarn .to contact and twist in the fibres on the fibre collecting surface of the rotor 5 and the reserve length of yarn between the delivery means and the yarn take-up means is taken up on the package 12.

The actuating member 47 contacts the pin 46 and 1 thereby causes the shaft 38 to rotate in an anticlockwise direction as seen in FIG. 3. Thus the finger member 55 is brought out of contact with the side of the housing 16 and the yarn released. The fork members 43, 44 move towards the delivery rollers 7, 8 to insert the yarn in the delivery roller nip so that normal delivery of the yarn commences.

The slide member 17 is returned and the trigger 32 re-set manually by use of a cocking handle 62.

The rate of travel of the slide member 17 may be controlled by a piston 31, attached to slide actuating lever 26, sliding in cylinder 30. The adjustable needle valve 57 controls the rate of exhaust of air from the cylinder 30 and thereby controls the rate of movement of the piston 31. In this way, the time interval between the release of the yarn y and the operation of the yarn delivery rollers 7, 8 may be varied.

In some open-end spinning machines the portion of yarn used in the piecing-up procedure is sucked away to waste through a take-up arrangement including a waste removal duct positioned after the delivery rollers 7, 8 so that yarn of unsuitable quality is not wound onto the package 12. In such an arrangement a shorter reserve length of yarn following the yarn delivery rollers may be used. In this arrangement the yarn is gripped by the finger member 55 after passing around the fork;

member 43, without engaging the first yarn holding means 18, 22. Thus this reserve length of yarn prevents the waste removal duct from absorbing yarn from the reserve length of yarn formed prior to the delivery rollers when the yarn is released by finger member 55 and before the yarn is placed in the delivery roller nip.

As mentioned above the yarn piecing up apparatus may be a portable unit which is transported to a particular station as desired or such an apparatus may be a fixed unit on a spinning machine. In the latter case the unit may incorporate a mechanism which reforms the first and second reserve lengths of yarn during the spinning operation so that they may be released on detec-- tion of an end breakage to effect a piecing up thereby assuming a continuous spinning operation. In a further arrangement the yarn piecing-up apparatus may be mounted on rails to serve a plurality of spinning machines and the apparatus moved along on the rails to the required spinning machine.

What we claim is:

1. A method of piecing-up yarn for an open-end spinning machine of the kind referred to comprising forming the yarn into an extended first yarn path and into an extended second yarn path to provide first and second reserve lengths of yarn respectively, and then, releasing the first and second reserve lengths of yarn, with the delivery of yarn halted to enable the first reserve length of yarn to enter the open-end spinning means and to enable the second reserve length of yarn to be taken-up by the take-up means and making operative the yarn delivery means to commence or recommence the formation, delivery and take-up of yarn.

2. A method according to claim 1 wherein the yarn delivery means are made-operative by re-engaging the yarn with the yarn delivery means upon release of the first and second reserve lengths of yarn.

3. A method according to claim 1 wherein the first and second reserve lengths of yarn are released before making operative the yarn delivery means.

4. A method according to claim 1 wherein the first and second reserve lengths of yarn are released simultaneously.

5. A method according to claim 1 and further comprising forming the first and second reserve lengths of yarn while the formation, delivery and take-up yarn are halted, then releasing the first and second reserve lengths of yarn and then commencing the formation, delivery and take-up of yarn.

6. A method according to claim 5 and further comprising reforming the first and second reserve lengths -of yarn after the commencement or re-commencement of the formation, delivery and take-up of yarn and then releasing the first and second reserve lengths of yarn upon end breakage of the yarn.

7. A method according to claim 1 and in which the open-end spinning means include a fibre feed device, wherein the formation of yarn is commenced or recommenced by starting the fibre feed device as the released yarn returns to the first and second yarn paths.

8. A method according to claim 1 and comprising holding the yarn against movement between the first and second reserve lengths of yarn and then releasing the yarn after the release of the first and second reserve lengths of yarn as the yarn delivery means and yarn take-up means and are made operative.

9. A method according to claim 1 and comprising commencing or re-commencing the delivery of yarn simultaneously with commencing or re-commencing the take-up of yarn.

10. Apparatus for piecing up an open-end spinning machine of the type in which yarn is formed in an openend spinning means and travels in a first path to yarn delivery means and in a second path from the yarn delivery means to yarn take-up means, the apparatus comprising:

a first yarn reserve length holding means which hold the yarn in an extended first yarn path to form a first reserve of yarn,

a second yarn reserve length holding means which hold the yarn in an extended second yarn path to form a second reserve of yarn, and

control means which, with the delivery of yarn halted,

control the release of the yarn from the first yarn reserve length holding means whereby the first reserve of yarn enters the open-end spinning means, and control the release of the yarn from the second yarn reserve length holding means to enable the second re- I serve of yarn to be taken up by the take-up means and which operate the yarn delivery means to commence the formation, delivery and take-up of yarn. 11. Apparatus according to claim 10 wherein the control means release the yarn from the first and second yarn reserve length holding means before making operative the yarn delivery means and wherein the control means include adjustable timing means for deter I mining the time interval between the release of the yarn and the operation of the yarn delivery means.

12. Apparatus according to claim 11 wherein the control means comprises an operating member which moves under the control of the timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means.

13. Apparatus according to claim 12 wherein the adjustable timing means comprise a pneumatic piston and cylinder arrangement which acts on the operating member.

14. Apparatus according to claim 10 wherein the first and second yarn reserve length holding means each comprise a pair of relatively movable parts, which in a first relative position hold the yarn in an extended yarn path and which are moved relatively to one another to a second position by the control means in which they release the yarn.

15. Apparatus according to claim 14 wherein the control means comprises an operating member which moves under the control of a timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means and wherein one part of each of the pairs of relatively movable parts is mounted on the operating member, the two parts of each pair being in their first relative position in the first position of the operating member and in their second relative position in the second position of the operating member.

16. Apparatus according to claim 10 wherein the formation and take-up of yarn is halted while the yarn is being engaged with the first and second yarn reserve length holding means, and wherein there is provided a microswitch for controlling the operation of the openend spinning means and the yarn take-up means, the control means operating said microswitch to make the open-end spinning means and the yarn take-up means operative after the first and second reserve lengths of yarn have been released and at the same time as the delivery means are made operative.

17. Apparatus according to claim 16 wherein the control means comprises an operating member which moves under the control of a timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means and wherein the microswitch is operated by the operating member in the third position of the operating member.

18. Apparatus according to claim 16 and in which the open-end spinning means include a fibre feed means whose operation is controlled by the microswitch whereby the fibre feed means commence operation upon operation of the microswitch.

19. Apparatus according to claim 10 wherein there is provided a yarn re-engaging means which, in a first position hold the yarn out of working engagement with the yarn delivery means to enable the yarn to be constrained into an extended yarn path and which are moved by the control means to a second position to reengage the yarn with the yarn delivery means when the yarn is released from the first and second yarn reserve length holding means.

20. Apparatus according to claim 19 wherein the control means comprises an operating member which moves under the control of a timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means and wherein the yarn re-engaging means are moved from said first position to said second position by the operating member in said third position of the operating member.

21. Apparatus according to claim 19 wherein the yarn re-engaging means also includes a yarn gripping member which grips the yarn between said first and second extended yarn paths until the yarn re-engaging means move to their second position when the yarn is released.

22. Apparatus according to claim 19 wherein the yarn re-engaging means comprise an arm means including yarn holding means and wherein the yarn delivery means comprise a pair of constantly contra-rotating rollers with a yarn engaging nip therebetween, the arm means being pivotable about an axis normal to the axis of the rollers on movement from said first position to said second position to insert the yarn into the nip of the rollers.

23. Apparatus according to claim 10 wherein the control means includes a manually operable trigger which, when operated, activates said control means to release the yarn and to commence or re-commence the formation, delivery and take-up of the yarn.

24. Apparatus according to claim 23 wherein the control means comprises an operating member which moves under the control of a timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means and wherein the release of the trigger means permits the operating member to move under the action of the timing means from said first position to said second and third positions.

25. Apparatus according to claim 24 wherein there is provided means whereby the operating member may be drawn back from said second and third position to said first position to reset the trigger. 

1. A method of piecing-up yarn for an open-end spinning machine of the kind referred to comprising forming the yarn into an extended first yarn path and into an extended second yarn path to provide first and second reserve lengths of yarn respectively, and then, releasing the first and second reserve lengths of yarn, with the delivery of yarn halted to enable the first reserve length of yarn to enter the open-end spinning means and to enable the second reserve length of yarn to be taken-up by the take-up means and making operative the yarn delivery means to commence or re-commence the formation, delivery and take-up of yarn.
 2. A method according to claim 1 wherein the yarn delivery means are made operative by re-engaging the yarn with the yarn delivery means upon release of the first and second reserve lengths of yarn.
 3. A method according to claim 1 wherein the first and second reserve Lengths of yarn are released before making operative the yarn delivery means.
 4. A method according to claim 1 wherein the first and second reserve lengths of yarn are released simultaneously.
 5. A method according to claim 1 and further comprising forming the first and second reserve lengths of yarn while the formation, delivery and take-up yarn are halted, then releasing the first and second reserve lengths of yarn and then commencing the formation, delivery and take-up of yarn.
 6. A method according to claim 5 and further comprising reforming the first and second reserve lengths of yarn after the commencement or re-commencement of the formation, delivery and take-up of yarn and then releasing the first and second reserve lengths of yarn upon end breakage of the yarn.
 7. A method according to claim 1 and in which the open-end spinning means include a fibre feed device, wherein the formation of yarn is commenced or re-commenced by starting the fibre feed device as the released yarn returns to the first and second yarn paths.
 8. A method according to claim 1 and comprising holding the yarn against movement between the first and second reserve lengths of yarn and then releasing the yarn after the release of the first and second reserve lengths of yarn as the yarn delivery means and yarn take-up means and are made operative.
 9. A method according to claim 1 and comprising commencing or re-commencing the delivery of yarn simultaneously with commencing or re-commencing the take-up of yarn.
 10. Apparatus for piecing up an open-end spinning machine of the type in which yarn is formed in an open-end spinning means and travels in a first path to yarn delivery means and in a second path from the yarn delivery means to yarn take-up means, the apparatus comprising: a first yarn reserve length holding means which hold the yarn in an extended first yarn path to form a first reserve of yarn, a second yarn reserve length holding means which hold the yarn in an extended second yarn path to form a second reserve of yarn, and control means which, with the delivery of yarn halted, control the release of the yarn from the first yarn reserve length holding means whereby the first reserve of yarn enters the openend spinning means, and control the release of the yarn from the second yarn reserve length holding means to enable the second reserve of yarn to be taken up by the take-up means and which operate the yarn delivery means to commence the formation, delivery and take-up of yarn.
 11. Apparatus according to claim 10 wherein the control means release the yarn from the first and second yarn reserve length holding means before making operative the yarn delivery means and wherein the control means include adjustable timing means for determining the time interval between the release of the yarn and the operation of the yarn delivery means.
 12. Apparatus according to claim 11 wherein the control means comprises an operating member which moves under the control of the timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means.
 13. Apparatus according to claim 12 wherein the adjustable timing means comprise a pneumatic piston and cylinder arrangement which acts on the operating member.
 14. Apparatus according to claim 10 wherein the first and second yarn reserve length holding means each comprise a pair of relatively movable parts, which in a first relative position hold the yarn in an extended yarn path and which are moved relatively to one another to a second position by the control means in which they release the yarn.
 15. Apparatus according to claim 14 wherein the control means comprises an operating member which moves under the control of a timing means frOm an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means and wherein one part of each of the pairs of relatively movable parts is mounted on the operating member, the two parts of each pair being in their first relative position in the first position of the operating member and in their second relative position in the second position of the operating member.
 16. Apparatus according to claim 10 wherein the formation and take-up of yarn is halted while the yarn is being engaged with the first and second yarn reserve length holding means, and wherein there is provided a microswitch for controlling the operation of the open-end spinning means and the yarn take-up means, the control means operating said microswitch to make the open-end spinning means and the yarn take-up means operative after the first and second reserve lengths of yarn have been released and at the same time as the delivery means are made operative.
 17. Apparatus according to claim 16 wherein the control means comprises an operating member which moves under the control of a timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means and wherein the microswitch is operated by the operating member in the third position of the operating member.
 18. Apparatus according to claim 16 and in which the open-end spinning means include a fibre feed means whose operation is controlled by the microswitch whereby the fibre feed means commence operation upon operation of the microswitch.
 19. Apparatus according to claim 10 wherein there is provided a yarn re-engaging means which, in a first position hold the yarn out of working engagement with the yarn delivery means to enable the yarn to be constrained into an extended yarn path and which are moved by the control means to a second position to re-engage the yarn with the yarn delivery means when the yarn is released from the first and second yarn reserve length holding means.
 20. Apparatus according to claim 19 wherein the control means comprises an operating member which moves under the control of a timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means and wherein the yarn re-engaging means are moved from said first position to said second position by the operating member in said third position of the operating member.
 21. Apparatus according to claim 19 wherein the yarn re-engaging means also includes a yarn gripping member which grips the yarn between said first and second extended yarn paths until the yarn re-engaging means move to their second position when the yarn is released.
 22. Apparatus according to claim 19 wherein the yarn re-engaging means comprise an arm means including yarn holding means and wherein the yarn delivery means comprise a pair of constantly contra-rotating rollers with a yarn engaging nip therebetween, the arm means being pivotable about an axis normal to the axis of the rollers on movement from said first position to said second position to insert the yarn into the nip of the rollers.
 23. Apparatus according to claim 10 wherein the control means includes a manually operable trigger which, when operated, activates said control means to release the yarn and to commence or re-commence the formation, delivery and take-up of the yarn.
 24. Apparatus according to claim 23 wherein the control means comprises an operatIng member which moves under the control of a timing means from an inoperative first position to a second position in which the operating member acts to release the yarn from the first and second yarn reserve length holding means and then to a third position in which the operating member acts to make operative the yarn delivery means and wherein the release of the trigger means permits the operating member to move under the action of the timing means from said first position to said second and third positions.
 25. Apparatus according to claim 24 wherein there is provided means whereby the operating member may be drawn back from said second and third position to said first position to reset the trigger. 